Rotary piston mechanism and its application to variable-speed gearing



Nov. 13, 19Z8. 1,691,479

H. HIORNS RQTARY PISTON MECHANISM AND ITS APPLICATION TO VARIABLE SPEED GEARING Filed May 11, 1925 3 Sheets-Sheet 1 Nov. 13, 1928.

H. HIORNS ROTARY PISTON MECHANISM AND ITS APPLICATION TO VARIABLE SPEED GEARING 3 Sheets-Sheet 2 Filed May 11, 1925 Nov. 13, 1928. 7 1,691,479

. H. HIORNS ROTARY PISTON MECHANISM AND ITS APPLICATION TO VARIABLE SPEED GEARING Filed May 11, 1925 a Sheets-Sheet 3 w w L R1 FQ t n,- E I E 5 f g @a) E 50 F a? wa l '2% R4 .i Fq

Patented Nov. 13, 1928 QFFJCEY angar moans, or 'rononaY, ENGLAND,

ROTARY PIfSTON TO VARIABLE-SPEED GEARING.

Application filed May 111, 1925, Serial No.

This invention comprises improvements in or relating torot ary piston mechanism'and its application to variable spee dgearing.

he mechanism to whichth': invention relates may be employed in various connections which include its use asfa pumpfa motor (for example, a steam eng ne, hydraulic. motor or with appropriate accessory parts asan e) me e? b wer ternal co 'nbustionleng or a clutch. According to the .inventlon there is. provided in'a rotary piston mechanism the com;' bination of a rotary element (for example a shaft) carrying a 'crank-pima hollo w cylindeifwhich is disposed with its longitiidinal' az-zis transver'se to "the axis of saidrotary element mounted for rotation about an" axis eccentric thereto and longitudinally slotted to receive the crank-pin, and a piston in said cylinder which is engagedby saidcrank-pin so tha'tit may be reciprocated in the cylinder by the crank-pin. Theeccentricity of the" axis of the cylinder should be equal 'to the radius of rotation of thecrank-pin and-the slot should cross this axis. i V

' It is found that the employr'nent of acylindrical'bore in the liollow'element, which receives the piston, andfthe' forihing of the piston so thatit' fits "this'cylindrical"bore results in motion' being transmitted between the rotary element and;the cylindrically bored elemcnt with a notable ab 'sence 01E noise and ba cklash 'which' are "commonly associated with such gears whe'nthe crank pins work in rectangular 'gr'ooves.""Tl1is is partly due to the fact that'the rectangular grooves in ordinary constructions cross'one another in the same plane and the guide blocks are not well supported passing over the crossingpoint. With'ac'ylindrical bore and a piston, however, the piston 1s well sup-- 7 ported throughout its Whole movement, and

even if more than one cylindrical bore is employed and both bores cross one another in the same plane, y'et owing to the cylin- (lrical shape the piston is satisfactorilysupported at the crossing point. e

Preferably the cylinder has an external enlargement on its wall which is slotted 1' sversely to the first said slot in the plane oi rotation of the cranlcpin'and therotary element has a second crank-pin which works in the slot in the boss. This second'slot and crank-pin ensure that there isalways a posi rive drive between the crank-shaft and the 29,466, and in Great Britain May 13, 1924.

pointof-t-he two slots should be in the axisof rotation of the cylinder.

The invention includes-a mechanism as described wherein corresponding slotsare provided"'thronglropposite parts of the cylinder wallgand the crank-pin extends through both slots: and engages a second'crank supported by'a rotarymember on the other side-of the cylinder from the first crank with .or without the provision on the cylinder of a second transversely 'slotted enlargement facing the second crankan'd acrank and a crank-pin therefor on the second crank. I The cylinder may be mounted on or formed in a disc with the cylinderbore in theplane of the disc, the disc may have two peripheral ports communicating with the two ends of the cylinder bore and a casing be provided which fits the periphery of the disc and has ports to co-operate' with the hC rts in the disc. P as already stated, one application of the invention is man internal combnstion engine. In oneform, an internal combustion engine according to' the invention'comprises a rotary 'pi'stonmechanism wherein the cylinder is mounted-on or formed in a disc as above described and theport in the-disc which communicates with one end of the 'cylinder'lies'inaplane '(taken parallel to the plane-of thedisc') which is a different planefi'o'm'that of the port-which communicates with the'other end of the cylinder, the casing so disposed as to deliver the charge to the other (power) endof the cylinder at a point of the rotation when the piston will be approachingm close to that e nd' of the cylinder, and an exhaust port for the power end o ffthe"cylinder, and wherein means are-provided for firing the charge.

'AJfurther important application of the mechanism according to the invention is to variable speed gears. Accordingto the invention an epicyclic variable speed-gear having a rotatable reaction member and means for clutching the reaction-member to another part of the mechanism when desired to vary the speed, is characterized-by the pros vision of a clutch the two elements of which a rotary piston mechanism as above described, and means for throttling the pas,- sage of a fluid into and out of the cylinder .so as to cause the clutch to operate.

One specific form of suchgear COIHPUSQS (for example a driven shaft) axially in line with the first rotary element and in operative engagement with said cylinder so as to turn therewith, means (for example a brake) for holding the carrier from rotation when desired, and adjustable means for closing the Working space of the cylinder so as to throttle the passage of fluid into and out of the cylinder.

The gear between the first said rotary element (for example the driving shaft) and the intermediate driver may consist of a crank and crank pin upon the said rotary element and a diametral slot in the intermediate driver engaged by said crank-pin, with or without a second crank pin and second diametral' slot transverse with the first.

There may be combined with these parts a controlling; device (for example a clutch member) for the intermediate driver which is engaged wlth the said driver by means which permit relative lateral displacement without relative angular movement, and means (for example a brake) to hold the controlling device from rotation when desired and thus to cause the two rotary elements to move in directionsopposite to one another. 7

Referring to the accompanying drawings:

Figure 1 is a vertical longitudinal crosssection through the piston mechanism when constructed to act as a pump;

Figure 2 is an elevation of the internal parts thereof looking in the direction 22 of Figure 1;

I Figure 3 is a vertical longitudinal section of the mechanism of an epicyclic variable speed gear constructed in accordance with the invention;

Figure 4 is an elevation showing the internal parts looking in the direction of the arrows 4& of Figure 3;

Figure 5 is a detail of the, control mecha nism; Figure 6 is a longitudinal sectional elevation of a modifiedspeed gear;

Figure 7 is a detail showing a modified means of control, and

bush in the half A of the casing.

Figures 8 and 9 are diagrams indicating the arrangement when applied to form an internal combustion engine.

Referring to Figures 1 and 2, the pump consists of a casing in'two halves A A and the mechanism enclosed thereby. A driving shaft B is supported in a bearing 2 3 The hearing A is sealed against leakage of water by a stuffing gland A and is provided with a lubricatorlfi. WVithin the casing the shaft B carries a crank disc B having two crank pins B B disposed diametrically opposite to one another,

A hollow cylinder C is formed diametricallyacross a disc C which is supported by a stub shaft C relatively to which the shaft B is displaced horizontally so as to be eccentric by an amount equal to the radius of the crank pins 13' B The disc C has a boss C on the side which faces the crank pins and this boss is slotted diametrically at C. In the slot 0 works a slide block C mounted on the crank pin B At right angles to the slot C is a slot 0 which is out, not only into the boss C but also through the cylinder wall. This slot is parallel to the bore of the cylinder and the crank pinB is made longer than the crank pin B so that it can pass beyond the slot C and enter the bore of the cylinder where it engages a piston D. r

The disc G makes a working fit against the casing on both faces near the periphery at G C The half A? of the casing is also 'iade to fit closely against the edge of the disc at two diametrically opposite places A A, while intermediately between these places ports A? A are formed in the casing which are open to the periphery of the disc. The open ends of the cylinder C form ports in the periphery of the disc C which co-operate with the ports A A The location of these ports is such that each of them is in communication with one end of the cylinder C during substantially the whole of one stroke of the piston. The port A is connected to a pipe .A" and the port A to a pipe-A The pipes A" and A act either as suction or delivery pipes, according to the direction of rotation. 1 l v In operationthe rotation of the shaft B causes the disc C to rotate'at one half of the speed of the shaft 13 by the action of the crank sins, and the piston D makes one complete reciprocation for each revolution of the disc C (i. e. it makes two strokes). 'It will be seen that the shaft C moves at only one half of the speed of the shaft B.

v The: shaft B may befldriven in any desired manner,'for example a pulley, as shown at E. Alternatively, the shaft C may be ex" tended as shown, and may carry a pulley E a suitable stuiiing box of course being provided onthe shaft C If the pulley E is driven the pump will have a different capac- It will be evidentthat by providing both pulleys Ell or equivalent means for re-i ceiving and transmitting power to and from v the shafts B and (P, a transmission gear is obtained ofa fixedv'elocityratio. 'This 1s eithe a reduction gear or a speed increasing gear according as E or E is the driver. If

the mechanism is to the used simply as a .transmission gear 1t,1s unriecessaryto make thecylinder U luid-tightorto make the disc C fit the casing I Referring to Figures 3 and 4 which show variable epicyclic gear, the. casing F F 1 houses a, dis C in which works a piston D similarly to the correspondingly lettered parts in Figures ram 2. The piston D is reciprocatedin the disc C by means ofthe crank pin B carried on a shaft B which in the present case constitutes an intermediate driver. The 'shaftC? will in general be the driven sl aft. The shaft B which, as already pointedout, is eccentric to the shaft C by an amount equal tothe radius of its crank pins is mountedin a carrier supported in hearings G which are concentric with the shaft C 5 The bush G in the carrier G which supports the shaft B is therefore eccentric. ,c The shaft B extends beyond the carrier G on thelside remote fromthe crank pinsand carries a gear wheel B which meshes with a gear wheeliH ona driving shaft H supported in a bearing F? in: the cas ng. i t

The driving shaft H is concentric with the bearings G for the-carrier G andwith the shaft C It is additionally supported by a bearing G? in the carrier V The carrier G has a brake disc G on it surrounded by a band brake K. The hand brake is normally held in the'ofl' position by a spring K (Figure 5.) but may be applied by rotation of an operating shaft K which brings a'cam-K to bear; upon the lugs K K at the extremities of the band K. The pipe A? whlch constitut s the delivery gof the pump portion of the mechanism is provided with a valve A and the two pipesA A are both connected to an oil reservoir.

In operation if the valve A is open and the hand brake K is applied so as toprevent rotation of the carrier G, then the intermediate driver B is rotated through the gears H in the opposite direction from'the shaft H at a reduced speed'and the disc C with the shaft C is rotated by theintermedr ate driver B in the same direction a-s'it is itself revolving but at one half the speed. Consequently the-shaft C rotates in the opposite direction to the shaft H at a considerable speed reduction. If the gear is used in a motor car this constitutes the reverse crlve. I

i Release of the brake K allows the gear to rotate idly withouttransmitting any torque. On now gradually closing the valve A re piston D by the crank pin 13 and torque in a forward direction is applied to theshaft C Ifthe valve A iscompletcly closed the piston l) is (neglecting leakage) prevented from movement in the cylinder the gear is locked, and the shaft H and shaft 0 with all. the intern'iediate mechanism rotate forwardly as-oue whole. This constitutes the direct drive for top speed in forward gear. \Vhenthe valv'eA is partly opened a certain amount oi. slip is allowed as with a slipping clutch which permits of the shaft C running at a lower speed than the shaft H.

- The ear illustrated in Fi ure 6c0ntains' replaced by a cross-slotted disc L on the intermediate driver, meshing with two crankpins H ll on a crank-disc H on the-drivmg shaft H. It will be noticed that the .L L in the disc L-take the form-of hoilow cylinders and the crank-pins H H engage pistons M M which work-in -the-cylinders, but as the mechanism is simply required to transmit power without acting as a clutch th pistons and cylinders need not be fluid-tight. It is found that these hollow cylinders and pistons work more silently than do rectangular slots and slide-blocks. The cylindrical slots L L cross one another in the same plane and this is possible when the pistons do not have to be fiuid-tight,- as they can then be made short-enough not to interfere with each other. 'This gear could be used in other connections than the one illustrated.

In the form shown in Figure 6 the disc L is provided with a controlling-membcr in the form of a brake-disc N supported to turn concentrically with the driving shaft H. Thebrake-disc N has circular recess N in which fit discs N engagedby pins K" on the disc L. The adius of the circular path of the pins K is equal to the radius of the crank pins H H and this again is equal to the eccentricity of the intermediate driver in the carrier G. A band brake O encircles the disc N and is controlled bya cam on the rock-shaft K in such a way that when the b 'ake Kis on the brake O is oil". An eccentric-L is let into the face of the disc L and has a bearing on the edge of the crank disc H so as to transmit side thrust between the parts. These parts are similar to the gear described in my co-pending patent, application Serial No. 756,432,1"1led 17th Deceml'icr, 1924 i p a "i -The operation is as follows: If the band brake O is-off and brake K is on the carrier Gris held from rotation, and the intern'iediate =sistance-is offered to the reciprocation of the driver 13 is driven by the shaft H at one half its speed through the gear L, L, L but unlike the gear illustrated in Figures 4 and 5 the direction of motion is not reversed. The intermediate driver acts as before described to turn the drivenshaft C at half its own speed, through the action of the disc C The result that the driven shaft rotates forwardly at one quarter speed. If now the valve A is slowly closed and the brake K slowly released, the speed will be gradually brought up to that of the driving shaft, the whole gear, as before, rotating solidly as one whole when the valve is shut Release of the valve and both brake-discs leaves the gear neutral-i. e., transmitting no torque. Applying the brake O, the brakedisc N is held from rotation and the disc L can only gyrate in a circular path parallel to itself. The effect is that the crank-pins H H cause it to gyrate in the reverse direction to the driving shaft at the same speed. The carrier G is carried round with it in this movement and the crank-pins B? I, acting on the slot G and piston D of the disc C impart to the disc C a movement in the same direction as the gyration of the disc L. l hus the driven shaft C moves at half speed in the reverse direction from the Sllf i1.

Figure 7 indicates a modification of the piston mechanism. In this case, instead of making the casing fit the disc aLlJl. table means areprovided on the disc itself for partlyor wholly closing the working space of the cylinder. In the formillustrated, the disc is made somewhat larger, and beyond the parts of the cylinder C in which works the piston D, the bore is traversed by cross bores C C Plugs I P lit these bores which are of suflicient diameter to allow the plugs to close the cylinder completely when fully home. The plugs are carried by a rotatable yoke P which is slidably mounted on a boss F inside the casing F and has a.

groove P to receive projections 1 from a stationary actuating-ring P The actuating ring is engaged by a push-rod P which through the wall of the casing. Thus cndwise movement of the push-rod I would open or close the working space of the cylinder, The casing F has anannular face F which. abuts on the disc C to retain the space around the disc ful of oil, but this joint is not subject to pressure therefore liable to such leakage as the joints around the disc shown in the other figures, which have to withstand oil-pressure Referring now to Figures 8 and 9 which indicate a form of internal combustion engine, it is to be understood that these fig ures are only diagrammatic and do not indicate any packing means, ignition, or other well known and necessary'parts of such an engine. Figure 8 is an elevation with the casing in section along the line 8-8 of Fig ure 9. Figure 9 is a plan with the casing insection alon the line 99 of Figure 8. The cylinder F in the disc C is-partly closed at each'end, but has portsC 0 at each end and. these ports are arranged to lie in different planes, taken parallel to the plane of the disc. The casing R has a circumferential rib R which separates the ports in the casing which communicate with the port C from those which communicate with the port C Aninlct port R? is pro- .vided in the plane of the port C to co operate therewith, and the port R communicates with an intake R An outlet port R is also provided in theplane of the port C to cooperate therewith and these ports R R are arranged as described withreference to Figures 1 and'Q so that the end of the cylinder C which communicates with the. port G acts as a pump to compress the reaches the exhaust port R communicating with the exhaust pipe It. Detailsof bearings and so forth are not shown but may be, broadly speaking, similar to those already describedwith reference to theother figures.

1. In a rotary piston mechanism the combination of a rotary element carrying'a pair of crank-pins, a cylindrically bored element which is disposed with the longitudinal axis of the bore transverse to the axis of said lil iii-s rotary element, is mounted for rotation 1 about an axis eccentric thereto, is longitu'dinally slotted to recelve one of the said crank-pins, has anexternal enlargement on its wall which is slotted transversely to the I first said slot in the plane of-rotation' of the crank-pins to receive the other of said crankpins, and a piston which fits in said cylindrical bore and is engaged by the first said crank-pin so that it may be reciprocated in the cylindrical bore by the crank-pin, substantially asand for the purposes described.

2. In a rotary piston mechanism the combination of. a rotary element carrying a crank-pin, a cylindrically bored element carried-by a disc with the cylinder bore in. the plane .of the disc, said disc being disposed so that the cylindrical borehas its longh tudinal axis transverse to the axis of said rotary element and said disc being mounted for rotation about an axis eccentric to the rotary element and slotted in a direction parallel with the cylindrical bore to receive the crank-pin, a piston which fits in said bore which is engaged by said crank-pin so that it may be reciprocated in the bore by he crank-pin, peripheral ports in the disc communicating with the two ends of the cylindrical bore, a casing which fits the periphery of the disc and ports in the casing to co-operate with the ports in the disc, substantially as and for the purposes described.

3. An epicyclie variable speed-gear having a rotatable reaction-member and means for clutching the reaction-member to another part of the mechanism when desired to vary the speed, characterized by the pro vision of a clutch the two elements of which are constituted by the cylinder and rotary member of a rotary piston mechanism having parts constructed and arranged as set forth in claim 1 and means for throttling the passage of fluid into and outof the cylinder to cause the clutch to operate.

4. An epicyclic variable speed-gear having a rotatable reaction-member and means for clutching the reaction-member to another part of themechanism when desired to vary the speed, characterized by the provision of a clutch the two elements of which are constituted by the cylinder and rotary member of a rotary piston mechanism having parts constructed and arranged as set .torth in claim 2 and means for throttling the passage of fluid into and out of the cylinder to cause the clutch to operate.

5. In an epicyclic variable speed gear the combination of a rotary torque-transmitting member, a carrier which is rotatably mounted to turn about an axls concentric with the torque-transmitting member, an intermediate driver geared with the rotary torquetransmitting member and supported in the carrier so as to be capable oi? rotation about an axis eccentric to the rotary torque-trans mitting member, a crank-pin upon the intermediate driver, a hollow cylinder disposed with its longitudinal axis transverse to the axis of said intermediate driver mounted for rotation about an axis concentric with said torque-transmitting member, and longitudinally-slotted to receive said crank-pin, a piston in said hollow cylinder, a rotary element axially in line with the torque-transmitting member and in operative engagement with said cylinder so as to turn thereand a diametral slot in the intermediate 7 driver engaged by said cranlcpin,

7 7. In an epicyclic variable speed-gear the combination with the parts set forth in claim 5 of a controlling device for the intermediate driver which is engaged with the said driver by means which permit relative lateral displacement without relative angular movement, and means to hold the controlling device from rotation when desired and thus to cause the two rotary elements to move in directions opposite to one another.

In testimony whereof I afiiX m si nature.

HARRY IoiaNs. 

